Patent GB-1509020-A (GB)
Title: Single lens reflex camera
IPC: G03B9/07
Filed: 1975-07-03
Abstract: 1509020 Single lens reflex cameras ASAHI KOGAKU KOGYO KK 3 July 1975 [12 July 1974] 27958/75 Heading G2A A single lens reflex camera has an operating lever connected to the minor and to delayed action shutter release mechanism and movable to set the delayed action mechanism and to raise the mirror, an operating button mounted coaxially with the lever to stop down the diaphragm, and an interlock to prevent the mirror from rising prematurely and the button from returning prematurely. As shown in Fig. 1, a lever 1 is fast with a sleeve 5 which turns in a bearing 4 mounted in the body 2 of the camera, and a stop-pin 3 for the lever is also mounted in body Z. A ball 8 and spring 7, together with a recess 1a in lever 1, form a click-stop. A pin 9 mounted on sleeve 5 enters an arcuate groove in a member 13 fixed to a cam 12, both being rotatably mounted on a shaft 16 journalled in frame plates 14, 15, so that when lever 1 is turned anti-clockwise, as viewed from above in Fig. 1, member 13 and cam 12 turn. A gear 17, fast with shaft 16, has a pin 18 extending into a groove 12a in cam 12. A member 20, mounted to rotate with shaft 16, carries a pin 21 connected to a spring 22 anchored to a fixed point on the camera body Z, and sets the self-timer mechanism, which is released by the shutter release rod 33, Fig. 4. Mirror release. As shown in Fig. 3, a lever 23 is spring-urged to pivot clockwise about a pin A fixed to the upper frame plate 14. The cam 12 acts on a part 23c of the lever to move it anticlockwise to the position shown in Fig. 4. A member 26 is urged by a spring 27 to pivot clockwise on a pin 24 mounted on lever 23. When lever 23 is in the position shown in Fig. 4, member 26 contacts a part 28 on a shutter release rod 33, and one end 27a of spring 27 bears against an anchor pawl 30 pivoted on a pin Q mounted on plate 14. This presses the pawl into engagement with a toothed wheel 31. A bifurcated portion 23a of the lever 23 engages a pin 32 which is part of the mirror operating mechanism (not shown), the mirror being held against movement when the parts are in the position shown in Fig. 4. Operation of the shutter release rod 33 causes part 28 to engage member 26 and rotate it anti-clockwise, moving the end 27a of spring 27 away from anchor pawl 30, which no longer engages toothed wheel 31. Wheel 31 is fast with member 20, Fig. 1, which is free to turn under action of spring 22, and so turns cam 12 back to its initial position. Lever 23 also returns, allowing pin 32 to be released, and the mirror is ready to be released. The parts may also be returned by manually returning lever 1 to its initial position. Manual stopping-down. A button 35, Figs.1, 7, is mounted coaxially with the lever 1 and slides therein. A screw 35a on the button moves along a slot 5a-5b in sleeve 5. The button has a casing 35b with a cap 35d; the casing is fixed to the top of the button and contacts a return spring 36. The lower end of the button is formed with a wedge-shaped portion 35e and a notch 35f, Fig. 7. When the button 35 is manually depressed, wedge portion 35e contacts a part 39d of a lever 39 (Figs. 1, 5), pivotally mounted on a pin B on body 2, so that lever 39 is retained in position against action of a memory lock lever 38, which is spring-urged to rotate clockwise on a shaft C, and which has an edge urged against a pin 39a on lever 39. A portion 39c of lever 39 engages and operates a pin 40, which is part of the stopping-down mechanism. Operation of the memory lock lever 38 operates a switch 44, Fig. 3, before stopping down so that the photometric measurement it supplied is unaltered by the stopping down. Mirror raising operation. When lever 1 is rotated clockwise, cam 12 and member 13 turn, rocking a lever 42 from the position shown in Fig. 5 to the position shown in Fig. 6. A lug 42a on the lever is in contact with a pin 43 connected to the mirror raising member.